Facile synthesis of reduced graphene oxide using Caesalpinia sappan L. extract as green reducing agent

Facile synthesis of reduced-graphene oxide (rGO) has been conducted in this study using the extract of Caesalpinia sappan L. as a green reducing agent. Graphite sheets were first exfoliated using an improved Hummer process to produce graphene oxide (GO). Then, the reduced-graphene oxide (rGO) was obtained by reducing GO with Caesalpinia sappan L. extract at various concentrations in an autoclave hydrothermal process. Analytical methods such as XRD, Raman spectroscopy, FTIR, SEM-EDX, TEM, UV–visible absorption, TG-DTA, and zeta potential value were used to characterize the graphite, GO, and rGO materials. A cyclic voltammetric study was also conducted to measure the performance of the synthesized materials. All rGO show good electrochemical properties, and the highest oxidation and reduction currents are observed for rGO-10. The characterization results show that Caesalpinia sappan L. extract can effectively reduce GO to rGO, and the best rGO can be obtained by adjusting the level of the extract.